1. Field of the Invention
The present invention generally relates to communication systems, and more particularly, to improved method and apparatus for actively characterizing data calls in a public switched telephone network (PSTN) in order to identify and distinguish data service providers from end users and voice calls, for purposes of improved call routing and distribution.
2. Discussion of the Related Art
As is known, the public switched telephone network (PSTN) in the United States is divided into geographic areas called Local Access and Transport Areas (LATAs). Local Exchange Carriers (LECs) may freely transport traffic within LATA boundaries, while Interexchange Carriers (IXCs) are required to manage traffic between LATAs. The LEC typically provides customers (non-pay-type telephones) with a flat rate billing area. In practice, these billing areas are groups of destination switches, from a given subscriber's own serving switch, which are considered local. Usage between these switches is billed on a flat rate, regardless of usage. Generally, only calls outside this local area are billed on a usage sensitive basis. As a result, there is virtually no incentive to lead customers to limit local calling.
As is further known, traffic within the PSTN is transported between switches using interoffice trunks. When a call is placed on a trunk circuit, that circuit is tied up and thus no longer available for use by other customers. For cost reasons, there is a such smaller number of trunk lines extending from a switch to neighboring switches, than there are customer phone lines connected to the switch. Therefore, trunk lines are a shared resource, generally allocated on a "first come first serve" demand basis.
Based upon traffic principles that are known by those in the art, switches are generally designed with a subscriber line/trunk line ratio to limit the number of blocked calls in an hour to about 1%. Certainly, however, this number will vary depending on a number of factors including the demand at a given time, the number of customers desiring to place a call, the length established calls are maintained, etc. Over the years, these voice calling patterns have been relatively constant, such that telephone company engineers could reliably design switches and networks to achieve an expected grade of service.
In recent years, however, telephone communication systems have changed. Largely due to the proliferation of the Internet, telephone networks are becoming increasingly jammed with data traffic, as opposed to voice traffic. Not only has this led to a stark increase in the number of calls that are placed, but empirical data has demonstrated that the duration of data calls lasts for a much longer period of time than voice calls. Specifically, studies conducted with Data Service Providers (e.g., Internet Service Providers) have indicated that the average call holding time for a data call can exceed 30 minutes, as opposed to approximately 3 minutes for voice calls.
Some evaluations have revealed that, in some switches, about 12% of the total terminating inter-switch calls were known Internet Service Providers, however, some 60% of the interswitch terminating traffic was to the same known ISPs. This has led to enormous problems for telephone company engineers who design switches. Unless the service provider has subscribed to a special service from the telephone company, such as ISDN or a DSL service, phone calls to and from Data Service Providers appear like any other PSTN call. Since these calls tend to tie up the phone lines for a longer period of use, they disrupt the call pattern anticipated in connection with the design of the network. As a result, a much higher than anticipated ratio of call blocking (due to busy lines) occurs.
Accordingly, it is desired to factor the calling characteristics of Data Service Providers into the design of the PSTN. This may be done by either evenly distributing Data Service Providers on switching hardware (i.e., line concentrator units), or by establishing data networks to handle data traffic. The problem lies in identifying Data Service Providers in the first place.
Simply stated, since Data Service Providers are not required to tell phone companies that they are offering data service, most don't. As a result, the phone companies generally rely on "shopping" for such Data Service Providers. To "shop", PSTN operators identify advertisements for Data Service Providers, and call them to order service to find the dial-in number. This method requires an expensive investment of operator time, and generates results that are "hit or miss" at best.
Accordingly, there is a present need to provide a reliable system or method for identifying Data Service Providers on the PSTN, so that appropriate considerations may be taken into account in the design of a LATA of the PSTN.